The invention relates generally to a safety plug adapter, which includes an overcurrent protection device, connected between a single phase, grounded, polarized electrical receptacle and a two or three prong electric plug for supplying electric power to an electrical appliance or device. More particularly, the invention relates to this type of safety plug adapter which includes safety features for protecting small children against contact with an energized electrical circuit.
Known safety plug adapters, such as those described in U.S. Pat. No. 3,368,110, issued Feb. 6, 1968 to R. A. Taylor, or in U.S. Pat. No. 2,649,522, issued Aug. 18, 1953 to M. J. Marcus, include fuses which will limit the magnitude and duration of overload or short circuit current. Thus, if a small child inserted a wire into the appertures of one of these known safety adapters which was plugged into a conventional wall receptacle to thus cause a short circuit current to flow through the wire, these fuses would provide some degree of protection to the child from burning caused by the heating and/or melting of this wire. However, the child could still be seriously injured. Also, there is nothing to prevent a small child from disconnecting one of these known safety plug adapters from the wall receptacle, and thereafter inserting a wire in the openings of the wall receptacle, in which case, a child could be seriously burnt by molten metal or subjected to severe electrical shock before a fuse or circuit breaker in the electrical supply line for the wall receptacle operates to disconnect this wall receptacle.
There are known plastic plugs of insulating material, which, when inserted in an electrical receptacle, are difficult for small children to remove. In households containing small children, these known insulating plugs can be used to cover unused electrical receptacles to protect such small children from contact with an energized conductor of the unused receptacle. However, there is also a need to better protect small children from contact with an energized electrical conductor of a receptacle which is normally used, since it is relatively easy for a small child to disconnect an electrical appliance, or device, such as a lamp, by merely tugging or jerking on the electric cord for this appliance.